| POLYMERS Vol.67 No.6 |
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COVER STORY
Moving Polymers |
| COVER STORY: Highlight Reviews |
| From the Synthesis of a Molecular Wheel to the First Nanocar Race | Gwénaël RAPENNE, Kazuma YASUHARA |
| <Abstract> This article present our work accomplished from the synthesis of molecular triptycenes wheels and their incorporation into two different prototypes of nanocars with a special focus on the green buggy, the french nanocar which participated to the first nanocar race organized in Toulouse (France) the 28th and 29th of April 2017. Six competitors from Austria, Germany, Japan, Switzerland, the United States and France met in Toulouse (France) to compete with their molecular racers. This event has been seen as a major communication event by the general public, but we will describe why it was also a highly challenging scientific event. Keywords: Nanowheel / Nanocar / Polyaromatic Hydrocarbon / Triptycene / Single Molecule / STM / Nanocar Race |
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| Fundamental Features of F1-ATPase and Engineering Approach | Hiroyuki NOJI, Hiroshi UENO |
| <Abstract> A variety of molecular motors move dynamically within the cells that results in the creation of diverse life phenomena. Among them, the rotary molecular motor F1-ATPase is one of the best characterized molecular motors. There are many high-resolution crystal structures and the rotation dynamics have been investigated in detail by extensive single-molecule studies. In this paper, we introduce the fundamental features of F1-ATPase and the enginnering approach for the re-designing of novel molecular motors. Keywords: Molecular Motor / F1-ATPase / ATP Synthase / Single-Molecule Techniques |
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| Alignment and Driving in Microphase Separated Structure by Light | Shusaku NAGANO |
| <Abstract> For creation of synthetic materials that drive macroscopic motions mimicking the living body, it is necessary to construct hierarchical motions flowing from molecular nanoscale to macroscale, seamlessly. Therefore, the important key is mesoscopic molecular organization designs between nano- and macroscale. This review focuses on the photochromic molecule “azobenzene” and its “liquid crystal” and introduce the photofunctional and mechanical polymer systems. Furthermore, optical alignment controls of microphase separated structure in liquid crystalline block copolymer thin films are also introduced as photomechanical systems that play an important role in mesoscale structures. These photoinduced hierarchical motions are expected to provide new concepts and possibilities for new polymer LC devices. Keywords: Photoresponsive Polymers / Liquid Crystals / Photoalignment / Photomechanical Effects / Block Copolymers / Microphase Separated Structure |
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| COVER STORY: Topics and Products |
| Sustainable Motion of Azobenzene Self-Assembly | Yoshiyuki KAGEYAMA |
| <Abstract> Since the early part of this century, there have been studies on mechanical working materials. According to the author's standpoint, there are two kinds of behaviors. One is stimuli-responsive (stimuli-controlled) motion, and the other is autonomous motion. Although most researchers are studying stimuli-responsive materials, the author is interested in the dynamics of the latter, in which the material evades the maximization of its own entropy by self-organization. Previously, the author reported the self-oscillatory motion of azobenzene containing co-crystals. The crystal repeated a flipping motion under continuous blue-light irradiation. The sustainable motion results from the cycle of (1) trans-to-cis photoisomerization, (2) crystalline-crystalline phase transition, (3) cis-to-trans photoisomerization, and (4) phase transition to the original crystal. Such limit-cycle oscillation is key for the ability to conduct dissipative mechanical tasks. Aiming to create so-called smart materials, which accomplish mechanical tasks by molecular structural transition, the author claims that it is necessary to develop studies of autonomous behaviors with time-delayed chemical dynamics. Keywords: Autonomous Motion / Dissipative Self-Organization / Chemical Oscillation / Reaction Cycle / Information Ratchet / Photoisomerization / Phase Transition / Molecular Assembly |
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| DNA Origami Machines Move | Akinori KUZUYA |
| <Abstract> Since its development in 2006, DNA origami technique has realized various useful and sophisticated two-dimensional and three-dimensional nano-devices. “DNA origami machines” with particular movement is one of the latest fruit of the technique. This article briefly describes our “DNA origami pinching devices”, one of the earliest DNA origami machines, which can be used as a single-molecular visual detector for biomolecules. Keywords: DNA Nanotechnology / DNA Origami / Molecular Machines / Allosteric Enzymes / Supramolecular Chemistry |
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| Move, Amoeba-Type Molbot | Yusuke SATO, Shin-ichiro M. NOMURA |
| <Abstract> One of the major goals of the micro-nano technology is to realize a tiny-wet robot, which is assembled from the molecular devices such as sensors, actuators, and even logic circuits. Significant progress in the field of biochemistry and molecular biology has been enabled to modify biomolecules and apply them to the construction of sensors, actuators, and logic circuits. These molecular devices can be utilized as the components of a “molecular robot”. We constructed an ameba-like molecular robot capable of expressing continuous shape change in response to specific signal molecules. The robot includes a main body, an actuator, and an actuator control device (molecular clutch). When the clutch was engaged, the robot showed continuous shape change. And when the clutch was disconnected, it stopped. These results show that the components of the robot are consistently integrated into the functional system. We are expecting that this research can provide a platform for constructing increasingly complex and functional molecular systems with controllable motility. Keywords: Molecular Robot / DNA Nanotechnology / Molecular Motors / Giant Liposome / Artificial Cell |
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| Polymer Science and I: A Personal Account |
| No Pain, No Gain | Toshiki SAWADA |
| <Abstract> My research in graduate school was fortunately succeded by my trial and error approach. My unsophisticated research style as an academic might have been established in this period. In this essay, I would like to describe how I have developed my research with patience by my own style. |
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| Front-Line Polymer Science |
| Structural Elucidation of Organic Polymer Materials by Dynamic Nuclear Polarization Solid-State NMR Spectroscopy | Shinji TANAKA, Kazuhiko SATO |
| <Abstract> Nuclear magnetic resonace (NMR) spectroscopy has been a powerful tool for structural elucidation of organic polymer materials since a long time. Solid-state NMR has suffered from drawbacks of low sensitivity and resolution owing to the chemical shift anisotropy, the dipolar coupling between nuclei typically seen in the solid state, although it provides a lot of information regarding the sturucture and dynamics of polymers in a nondestructive way. Recently, NMR spectroscopy with dynamic nuclear polarization (DNP-NMR) allows us to characterize the surface species on various materials including organic polymers. The DNP effect enhances the sensitivity of NMR by the microwave-driven polarization transfer of eletron spin polarization to nuclei. In this review, we highlight recent advances of the characterization of organic polymer materials by DNP-NMR. Keywords: Dynamic Nuclear Polarization (DNP) / Solid-State NMR / Organic Polymer / Material / Radical |
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